It seems the kernel error 41 is just the typical unexpected shutdown message... it can be literally anything.
In my case, every shutdown has the following log entry in the event viewer (just noticed it now):
ACPI thermal zone ACPI\ThermalZone\TZS1 has been enumerated.
_PSV = 0K
_TC1 = 0
_TC2 = 0
_TSP = 0ms
_AC0 = 0K
_AC1 = 0K
_AC2 = 0K
_AC3 = 0K
_AC4 = 0K
_AC5 = 0K
_AC6 = 0K
_AC7 = 0K
_AC8 = 0K
_AC9 = 0K
_CRT = 369K
_HOT = 0K
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>89</EventID>
<Version>0</Version>
<Level>4</Level>
<Task>86</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000020</Keywords>
<TimeCreated SystemTime="2015-05-05T16:31:09.420019200Z" />
<EventRecordID>21661</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="52" />
<Channel>System</Channel>
<Computer>pc-PC</Computer>
<Security UserID="S-1-5-18" />
</System>
- <EventData>
<Data Name="ThermalZoneDeviceInstanceLength">21</Data>
<Data Name="ThermalZoneDeviceInstance">ACPI\ThermalZone\TZS1</Data>
<Data Name="AffinityCount">1</Data>
<Data Name="_PSV">0</Data>
<Data Name="_TC1">0</Data>
<Data Name="_TC2">0</Data>
<Data Name="_TSP">0</Data>
<Data Name="_AC0">0</Data>
<Data Name="_AC1">0</Data>
<Data Name="_AC2">0</Data>
<Data Name="_AC3">0</Data>
<Data Name="_AC4">0</Data>
<Data Name="_AC5">0</Data>
<Data Name="_AC6">0</Data>
<Data Name="_AC7">0</Data>
<Data Name="_AC8">0</Data>
<Data Name="_AC9">0</Data>
<Data Name="_CRT">369</Data>
<Data Name="_HOT">0</Data>
<ComplexData Name="_PSL">0000000000000000</ComplexData>
</EventData>
</Event>
It seems to be related to overheating... but this makes no sense for a laptop to overheat right after being turned off for a night. After turning on most temperatures are around 40-50C as well according to speedFan. I have had quite a few 80-90c temperatures in the past but only when playing games.